Waterproofing membranes made up of refined asphalts, synthetic rubbers, and extenders have been widely used for several decades for sealing horizontal, vertical, or transverse surfaces. Such waterproofing membranes are characterized by a high degree of flexibility over a wide temperature range, the ability to self heal when lightly damaged, tenacious adherence to the surface to which they are applied, the ability to bridge relatively wide cracks without the need for flashing, and extreme longevity.
One class of such waterproofing membranes, referred to hereinafter as "viscous membrane" and exemplified by Liquid Membrane 6125.RTM. manufactured by American Hydrotech, Inc., Chicago, Ill., is very popular and widely used due to its exceptional functional characteristics. Typically, viscous membrane is heated to about 400.degree. F. prior to application so as to liquefy the material and reduce its viscosity to a point where it is spreadable. Then, the viscous membrane is poured onto a surface and is spread out using conventional spreading tools.
Viscous membrane tends to be difficult to transport from the kettle where the membrane is liquefied to the surface on which the material is to be applied when the surface is remote from the kettle. This difficulty arises due to the tendency of the material to freeze to the wall of the container in which it is being transported if the material remains in the container for more than about 15 minutes. For instance, when the viscous membrane is to be applied to the roof of a multi-story structure and fire code or other considerations require that the kettle in which the viscous membrane is heated be positioned on the ground adjacent the structure, rather than on the roof, it is not uncommon for the membrane to build up on the walls of the containers in which it is transported such that after three or four loads the containers are completely filled with solid viscous membrane. Then, the solid viscous membrane must be melted out of the containers using known processes which are time and labor intensive.
To avoid the above-noted freeze-up problems associated with transporting viscous membrane, an attempt was made in Canada to develop a system for pumping liquefied viscous membrane from the kettle in which it is stored through a pipe to a location remote from the kettle. The system was designed for use with a conventional oil-jacketed, gas jet-fired kettle of the type manufactured by Industrial Waterproof Systems, Ltd., Calgary, Alberta, and identified as a seven-proof melter. Such a kettle has a chamber for receiving the viscous membrane which is about 3 feet deep. The system included a conventional pump of the type used to pump liquefied roofing asphalt, and a pipe assembly coupled to the output of the pump for transporting the viscous membrane to a remote location. The intake for the pump was positioned in the chamber of the kettle just below the surface level of the liquefied viscous membrane stored in the chamber. The kettle was located on a substantially level surface, and was level with respect to the surface. The pipe assembly included a plurality of pipe sections, each comprising an inner pipe, an outer pipe surrounding and coupled with the inner pipe, and insulation positioned between the inner and outer pipes. The pipe sections were designed to be attached end-to-end so as to form a continuous elongate pipe assembly. Each inner pipe included a heating coil which was only slightly longer than the length of the pipe. As a consequence of the length of the coil it is believed that the latter was wrapped only once around the inner pipe. The heating coils were designed to be powered by 110 volt source, with a separate power cord being provided for the heating coil of each pipe section.
Unfortunately, it is believed that the above-described system did not function effectively.
Other systems and devices are known for storing asphalt-based roofing and paving materials in a liquefied and/or heated state, and for transporting such materials from one location to another location. For instance, devices for storing asphalt-based materials in a liquid state and for pumping such materials to a remote site are disclosed in U.S. Pat. Nos. 3,033,245; 3,359,970; 3,841,527; 4,247,022; and 4,620,645. Heated pipe systems for transporting heated, liquefied materials such as roofing asphalt are disclosed in U.S. Pat. Nos. 2,824,209; 3,378,673; 3,789,188; 4,455,474; and 4,667,084. Systems for storing and transporting heated asphalt-based materials are disclosed in U.S. Pat. Nos. 198,359; 1,931,793; 3,301,441; 3,622,748; and 4,028,527.
It is believed that none of the systems described in the above-listed patents are designed to store and transport liquefied viscous membrane which has been heated to a temperature of about 400.degree. F. both the temperature and the high viscosity of viscous membrane would tend to render the systems described in the above-listed patents inoperative, or may even destroy such systems.
As a consequence of the failure of the above-described system for pumping viscous membrane, and due to the inapplicability of the devices disclosed in the above-noted patents as means for storing and transporting viscous membrane, a strong need continues to exist for a system for transporting viscous membrane from the kettle where it is liquefied to a remote location. Such a system is desired by the construction industry because the labor costs associated with applying viscous membrane on a surface remote from the kettle where the membrane is liquefied are often double those incurred when the kettle is positioned near or on the surface. In addition, such a system is desired because structural and fire safety considerations often make it unfeasible to place the kettle for heating viscous membrane on the roof on which viscous membrane is to be applied.